`AZam et al.
`
`USOO5860963A
`Patent Number:
`11
`(45) Date of Patent:
`
`5,860,963
`Jan. 19, 1999
`
`54). GUIDING CATHETER
`
`Logan, Plymouth; Brad J. Wessman,
`
`75 Inventors: Nusayr Azam, Minneapolis; John B.
`Crystal; William R. Priedeman,
`Wayzata, all of Minn.
`73 Assignee: Schneider (USA) Inc, Plymouth, Minn.
`
`5,078,702
`
`1/1992 Pomeranz - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 604/280
`
`4,994,047 2/1991 Walker et al. .......................... 604/280
`5,045,072 9/1991 Castillo et al..
`5,061,257 10/1991 Martinez et al..
`5,276 2: Sile et al.
`5.254.107 10/1993 Soltesz.
`5,279.596
`1/1994 Castaneda et al..
`f
`aSaCCaC a
`FOREIGN PATENT DOCUMENTS
`1160531
`1/1984 Canada.
`21 Appl. No. 751,342
`0121215 10/1984 European Pat. Off..
`1-1.
`0473045 3/1992 European Pat. Off..
`22 Filed:
`Nov. 19, 1996
`0520692 12/1992 European Pat. Off..
`O
`O
`0542246A1 5/1993 European Pat. Off..
`Related U.S. Application Data
`9113648 9/1991 WIPO.
`9215356 9/1992 WIPO.
`63 Continuation of Ser. No. 165,127, Dec. 10, 1993, aban-
`93OO953 1/1993 WIPO.
`doned.
`Primary Examiner Ronald Stright
`51) Int. Cl. .................................................... A61M 25/00
`Attorney, Agent, or Firm-Peter C. Richardson; Lawrence
`52 U.S. Cl. .......................... 604/280; 604/282; 138/124;
`C. Akers; Philip C. Strassburger
`138/138
`58 Field of Search ..................................... 604/264, 280,
`57
`ABSTRACT
`604/281–283, 93; 138/123, 124, 125,137.
`138, 140, 153; 600/433, 434, 435 A catheter is disclosed having a proximal Shaft formed from
`an inner liner formed from a copolymer of polyvinylidene
`fluoride and hexafluoropropylene, an outer jacket formed
`References Cited
`from a blend of nylon and polyether block amide or poly
`U.S. PATENT DOCUMENTS
`ether block amide alone, and a soft flexible tip affixed to the
`distal end of the proximal shaft formed from polyether block
`E. E. ST,
`amide. A stem may be located between the proximal shaft
`4.250.072 3.E.
`r. et al. .
`and the soft flexible tip. The stem has an outer jacket formed
`4282.876 8/1981 FRAn.
`from a proximal Stem transition sleeve with a tapered distal
`4.283.447 8/1981 Flynn
`end and a distal Stem sleeve with a complementary tapered
`4,345,602 8/1982 Yoshimura et al..
`proximal end connected to the tapered distal end of the
`4,425,919
`1/1984 Alston, Jr. et al. ..................... 128/658
`proximal stem transition sleeve. The Stem transition sleeve
`4,464,176 8/1984 Wijayarathna.
`and the stem sleeve are both formed from polyether block
`4,531943 7/1985 Van Tassel et al..
`amide alone or a blend of polyether block amide and nylon.
`4,563,181
`1/1986 Wijayarathna et al. .
`The outer jacket may be the same hardneSS as or harder than
`4,596,563
`6/1986 East
`
`E. E. S. o 604/280 the stem transition sleeve which in turn is harder than the
`4.736768 4f1988 Fion
`stem sleeve and the soft flexible tip. An intermediate wire
`4,816,339 3/1989 Tu et al... 62366
`mesh braid extends through the proximal shaft and, if
`4,817,613 4/1989 Jaraczewski et al. .
`desired, through the stem.
`4,886,506 12/1989 Lovgren et al..
`4,898,591
`2/1990 Jang et al..
`
`6
`
`56)
`
`38 Claims, 2 Drawing Sheets
`
`23
`
`30
`
`22
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`21
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`U.S. Patent
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`Jan. 19, 1999
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`Sheet 1 of 2
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`Medtronic Exhibit 1476
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`U.S. Patent
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`Jan. 19, 1999
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`Sheet 2 of 2
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`Page 3
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`Medtronic Exhibit 1476
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`
`1
`GUIDING CATHETER
`
`5,860,963
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`This is a continuation of application Ser. No. 08/165,127
`filed on Dec. 10, 1993, now abandoned.
`BACKGROUND OF THE INVENTION
`Guiding catheters are commonly used during coronary
`angioplasty procedures to aid in delivering a balloon cath
`eter or other interventional medical device to a treatment Site
`in a coronary vessel. In a routine coronary angioplasty
`procedure, a guiding catheter is introduced into a peripheral
`artery and advanced over a guidewire through the aorta until
`the distal end of the guiding catheter is engaged with the
`appropriate coronary ostium. Next a balloon dilatation cath
`eter is introduced over the guidewire and through the
`guiding catheter. The guidewire is advanced past the distal
`end of the guiding catheter within the lumen of the diseased
`vessel and manipulated across the region of the Stenosis. The
`balloon dilatation catheter is then advanced past the distal
`end of the guiding catheter over the guidewire until the
`balloon is positioned across the Stenotic lesion. After the
`balloon is inflated to dilate the blood vessel in the region of
`the Stenotic lesion, the guidewire, balloon dilatation catheter
`and guiding catheter are withdrawn.
`Guiding catheters typically have preformed bends formed
`along their distal portion to facilitate placement of the distal
`end of the guiding catheter into the ostium of a particular
`coronary artery of a patient. In order to function efficiently,
`guiding catheters should have a relatively Stiff main body
`portion and soft distal tip. This stiffness has been provided
`in the past by using a reinforced construction or by using
`certain relatively stiff polymeric materials. The stiff main
`body portion gives the guiding catheter Sufficient "pushabil
`ity” and “torqueability” to allow the guiding catheter to be
`inserted percutaneously into a peripheral artery, moved and
`rotated in the vasculature to position the distal end of the
`catheter at the desired Site adjacent to a particular coronary
`artery. However, the distal portion should have sufficient
`flexibility So that it can track over a guidewire and be
`maneuvered through a tortuous path to the treatment site. In
`addition, a Soft distal tip at the very distal end of the catheter
`should be used to minimize the risk of causing trauma to a
`blood vessel or even puncturing the vessel wall while the
`guiding catheter is being moved through the vasculature to
`the proper position. Such a soft tip is described in U.S. Pat.
`No. 4,531,943. In addition, the inner surface of the guiding
`catheter should be lubricous to facilitate movement of
`guidewires, balloon catheters and other interventional medi
`cal devices therethrough.
`Guiding catheters currently on the market attempt to
`achieve these goals with varying degrees of Success.
`However, none of the previous or current designs have
`heretofore provided an optimum combination of features
`that yield a catheter with a stiff main body portion, a flexible
`distal portion and a Soft distal tip that can be Successfully
`used in coronary angioplasty procedures.
`Therefore it would be desirable to provide a guiding
`catheter that has Sufficient rigidity along its proximal portion
`for enhanced pushability and torqueability, yet has a flexible
`distal portion and Soft tip to provide enhanced trackability
`and minimize trauma to the vessel wall.
`It would also be desirable to provide a guiding catheter
`that has a lubricous inner Surface to facilitate movement of
`guidewires, balloon catheters and other interventional
`devices therethrough.
`It would be further desirable to provide a guiding catheter
`that is easy to manufacture.
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`SUMMARY OF THE INVENTION
`These and other objects are achieved by the guiding
`catheter of the present invention. This guiding catheter has
`a bodystock and a Soft distal tip. The bodystock has an inner
`liner, an intermediate wire mesh braid and an outer jacket.
`The inner liner is formed from a copolymer of polyvi
`nylidene fluoride (PVDF) and hexafluoropropylene (HFP).
`The outerjacket is made from a blend of nylon and polyether
`block amide (PEBA) or from PEBA alone. The soft distal tip
`is formed from PEBA and is injection molded onto the distal
`end of the bodystock.
`The guiding catheter of this invention can also include a
`stem. The Stem is comprised of a stem transition sleeve and
`a stem sleeve that fits over the inner liner along a distal
`portion of the bodystock. The Stem transition sleeve has a
`tapered distal portion. The Stem sleeve has a tapered proxi
`mal portion that complements the taper of the Stem transition
`sleeve. The Outer jacket of the bodystock along this distal
`portion is removed to allow the Stem transition sleeve and
`Stem sleeve to be fitted thereon. In addition, the Stem may
`have a braided reinforcement therein.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`The above and other objects and advantages of this
`invention will be apparent upon consideration of the fol
`lowing detailed description, taken in conjunction with the
`accompanying drawings, in which like reference characters
`refer to like parts throughout and in which:
`FIG. 1 is a plan view of one embodiment of the guiding
`catheter of this invention with a portion of the catheter
`removed to show the construction of the bodystock;
`FIG. 2 is a longitudinal sectional view of the distal portion
`of one embodiment of the guiding catheter of this invention
`prior to the attachment of the Stem and tip;
`FIG. 3 is a longitudinal sectional view of the stem
`transition Sleeve and Stem sleeve prior to assembly of the
`guiding catheter of this invention;
`FIG. 4 is a longitudinal sectional view of the distal portion
`of one embodiment of the guiding catheter of this invention;
`and
`FIG. 5 is a plan view of the distal portion of the guiding
`catheter of this invention showing the Stem transition sleeve,
`Stem sleeve and Soft tip.
`DETAILED DESCRIPTION OF THE
`INVENTION
`One embodiment of the invention is a guiding catheter 10
`which has a tubular bodystock 20 and a soft tip 30 attached
`to the distal end of bodystock 20. Guiding catheter 10 can
`have any desired inner diameter and Outer diameter. Typical
`dimensions are an inner diameter of between about 0.050
`inches to about 0.130 inches (0.127 cm to 0.330 cm) and an
`outer diameter of about 0.070 inches to about 0.150 inches
`(0.178 cm to 0.381 cm). A conventional polycarbonate hub
`40 is attached to the proximal end of bodystock 20. In
`addition, an injection molded strain relief tube 50 is con
`nected to hub 40 and the proximal portion of bodystock 20.
`Strain relief tube 50 preferably has a tapered design as
`shown in FIG. 1. However, a constant outside diameter
`construction could also be used. The material used to
`produce strain relief tube 50 is a polyether block amide
`(PEBA) having a hardness of 25 D to 63 D. The PEBA may
`be mixed with up to 50% nylon, preferably nylon-12, 15%
`to 36% barium sulfate for radiopacity and either 4% titanium
`dioxide or 0.5% organic pigment as a colorant.
`
`Page 4
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`Medtronic Exhibit 1476
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`
`3
`Bodystock 20 is formed from an inner liner 21, an
`intermediate wire mesh braid 22 and an outer jacket 23.
`Inner liner 21 is formed from a copolymer of polyvinylidene
`fluoride (PVDF) and hexafluoropropylene (HFP). HFP is
`used to enhance the ability of inner liner 21 to be plasma
`etched to facilitate the attachment of outer jacket 23 thereto.
`Preferably 10% HFP is used. Suitable PVDF/HFP copoly
`mer can be obtained from Solvay under the designation
`Solef. The PVDF/HFP copolymer preferably has a thickness
`of between about 0.0010 inches (0.0025 cm) and about
`0.0050 inches (0.0127 cm).
`Inner liner 21 when formed from a PVDF/HFP copolymer
`provides a lubricous Surface facing the lumen of guiding
`catheter 10. This facilitates the passage of other medical
`devices therethrough. In addition, the use of a PVDF/HFP
`copolymer for inner liner 21 allows guiding catheter to be
`gamma Sterilized. Other prior catheters that use a polytet
`rafluoroethylene (PTFE/Teflon) inner liner cannot be
`gamma sterilized because PTFE is not gamma stable. If
`gamma sterilization will not be used, PVDF could be
`combined with another polymer Such as PTFE. In addition,
`the PVDF/HFP copolymer can be extruded continuously.
`This contributes to the ease of manufacture of the resulting
`product.
`Intermediate wire mesh braid 22 is formed from stainless
`steel wires braided over inner liner 21. Although stainless
`Steel wire is preferred, other Suitable materials. Such as
`Kevlar, or various polymer filaments could also be used. The
`Stainless Steel wire has a circular croSS-Section with a
`diameter of between about 0.0010 inches (0.0025 cm) and
`about 0.0030 inches (0.0076 cm). Alternatively, a flat wire
`could be used. Any Suitable braid pattern can be used for
`intermediate wire mesh braid 22. Preferably a 16 wire
`Stagger braid pattern is used. In this pattern each wire is
`helically wound around inner liner 21 in a two over and two
`under braided manner. The braid angle, as measured from
`the plane perpendicular to the longitudinal axis of guiding
`catheter 10, can be between about 15 degrees and about 60
`degrees with 30 degrees being preferred.
`Outer jacket 23 is formed from PEBA alone or from a
`blend of PEBA and nylon. Suitable PEBA can be obtained
`from Atochem under the designation Pebax. Suitable nylon
`can be obtained from Huls, America under the designation
`Vestamid. Outer jacket 23 preferably has a durometer of
`between about 63 D and about 72 D. When a blend of nylon
`and PEBA is used for outer jacket 23, preferably up to 50%
`nylon-12 is used. The use of PEBA alone or blended with
`nylon provides a bodystock material that is sufficiently stiff
`So that guiding catheter 10 has a proximal portion with
`enhanced “pushability” and “torqueability”.
`Optionally the PEBA or nylon and PEBA blend for outer
`jacket 23 can be mixed with a radiopaque material. Suitable
`materials are barium Sulfate, bismuth Subcarbonate, bismuth
`trioxide and bismuth oxychloride. Preferably a 36% by
`weight loading of barium Sulfate is used. Lesser or greater
`amounts of barium Sulfate can be used to make outer jacket
`23 leSS radiopaque or more radiopaque as the case may be.
`A pigment can also be used to color outer jacket 23. If Such
`a pigment is used, preferably 0.5% by weight is used. Lesser
`or greater amounts of the pigment can be used depending on
`the color desired.
`Soft tip 30 constitutes the most distal end of guiding
`catheter 10. It is formed from PEBA Such as the PEBA used
`for outer jacket 23. Preferably soft tip 30 has a durometer of
`between about 25 D and about 40 D. This gives soft tip 30
`a Softness that is Sufficient to minimize the chances of
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`damage to the inner Surface of a blood vessel through which
`guiding catheter 10 may pass. In addition, it is hard enough
`to maintain an opening therethrough to allow the passage of
`a guidewire, balloon catheter or other interventional medical
`device to pass out of the distal end of soft tip 30. Soft tip 30
`can be made radiopaque by mixing 15% by weight barium
`sulfate with the PEBA. Of course greater or lesser amounts
`of barium Sulfate or other radiopaque filler can be used. A
`4% by weight loading of titanium dioxide can be used to
`color Soft tip 30. Again greater or lesser amounts of titanium
`dioxide can be used. Preferably soft tip 30 has a length of
`between about 0.060 inches (0.15 cm) to about 0.20 (0.51
`cm) inches.
`Preferably guiding catheter 10 has a stem 150 located
`between bodystock 20 and soft tip 30. Stem 150 is composed
`of stem transition sleeve 51 and a stem sleeve 52. Stem
`transition sleeve 51 is formed from 40 D to 70 D PEBA
`blended with up to 50% nylon by weight. In addition, 36%
`barium sulfate by weight and 0.5% by weight of an organic
`pigment can be used. Again greater or lesser amounts of
`barium sulfate and the pigment can be used. Stem sleeve 52
`is formed from 25 D to 40 D PEBA with up to 50% by
`weight of nylon. In addition, 15% to 36% by weight of
`barium sulfate can be used. Finally, 4% by weight of
`titanium dioxide or 0.5% by weight of an organic pigment
`can be used to provide color to Stem sleeve 52. Again greater
`or lesser amounts of barium Sulfate and the pigment can be
`used.
`Stem transition sleeve 51 has a taper along the distal
`portion. Preferably this taper is 20 degrees but can be from
`about 10 degrees to about 30 degrees. Stem sleeve 52 has a
`complementary taper along its proximal portion to provide
`a Smooth transition between stem transition sleeve 51 and
`stem sleeve 52. The length of stem sleeve 52 can vary
`depending on the length of the distal portion of guiding
`catheter 10 that is desired to be flexible. Preferably stem
`sleeve 52 can be from about 0.45 inches (1.14 cm) to about
`2.1 inches (5.33 cm) as measured from its most distal end to
`the most proximal end of the taper. In addition, stem 150 can
`have a total length of between about 0.5 inches (1.27 cm) to
`about 6 inches (15.24 cm).
`Stem transition sleeve 51 and stem sleeve 52 fit over the
`distal portion of bodystock 20 where outer jacket 23 and, if
`desired, braid 22 have been removed. This configuration
`provides a Smooth transition in the flexibility of guiding
`catheter 10 from its proximal end to its distal end. This
`smooth transition from the high hardness/stiffness of bod
`ystock 20 to the high softness of soft tip 30 eliminates stress
`concentration at the Stem to bodystock joint. High StreSS
`concentrations at this joint would promote kinking and
`failure of guiding catheter 10.
`Guiding catheter 10 can be manufactured according to the
`following process. A thin layer of PVDF/HFP copolymer is
`extruded over a Silicone impregnated acetal core rod to form
`inner liner 21. The PVDF/HFP copolymer is plasma etched
`in an argon/oxygen atmosphere. Other atmospheres, Such as
`an ammonia atmosphere, could also be used. Preferably a
`molar ratio of 70 to 30 argon to oxygen is excited by an
`electrical current of 550 watts in a vacuum of 200 millitorr.
`The residence time of innerjacket 21 is Six minutes. This gas
`plasma chemically modifies the Surface of the copolymer as
`it passes through the plasma field. This Surface modification
`leaves active molecular bonding sites free to attach to the
`polymer molecules in the Second jacket. Of course this
`Surface modification could be achieved by chemically etch
`ing the copolymer with, for example, butyl amine. The
`plasma etching Step can occur either before or after the
`
`Page 5
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`Medtronic Exhibit 1476
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`
`
`S
`braiding Step. A plurality of StainleSS Steel wires are braided
`around the PVDF/HFP inner liner 21. The number of wires
`used is a function of the diameter of the catheter to be
`formed and the desired rigidity for the catheter. The PEBA
`or nylon/PEBA blend outer jacket 23 is extruded over wire
`mesh braid 22. For the stemless embodiment, the distal end
`of the resulting assembly is ground and soft tip 30 is
`injection molded thereto.
`In the Stemmed embodiment, a distal portion of outer
`jacket 23 and, if desired, a corresponding length of braid 22
`is removed. Then a pre-extruded stem transition sleeve 51
`and a pre-extruded Stem sleeve 52 are slipped over the distal
`portion and RF welded in place. Soft tip 30 is injection
`molded to the distal end of this assembly.
`Thus it is seen that a guiding catheter is provided that has
`a lubricous inner Surface and is Sufficiently rigid along its
`proximal length to provide “pushability” and “torqueability”
`yet is flexible along its distal portion and has a distal Soft tip
`to provide enhanced trackability and to minimize trauma to
`the vessel wall. One skilled in the art will appreciate that the
`described embodiments are presented for purposes of illus
`tration and not of limitation and the present invention is only
`limited by the claims which follow.
`We claim:
`1. A catheter comprising:
`an elongate proximal tube having a proximal end and a
`distal end with an exposed innermost liner formed from
`a material consisting essentially of a copolymer of
`polyvinylidene fluoride and hexafluoropropylene, an
`intermediate reinforcing layer and an outer jacket
`formed from a material including a blend of nylon and
`polyether block amide or polyether block amide alone;
`and
`a Soft flexible tip formed from a material including
`polyether block amide affixed to the distal end of the
`elongate proximal tube,
`wherein the catheter is stable upon exposure to gamma
`radiation.
`2. The catheter of claim 1 wherein the material forming
`the outer jacket is harder than the material forming the Soft
`flexible tip.
`3. The catheter of claim 2 wherein the material forming
`the outer jacket has a hardneSS in the range of about 63D to
`about 72 D and the material forming the soft flexible tip has
`a hardness in the range of about 25 D to about 40 D.
`4. The catheter of claim 3 wherein the intermediate
`reinforcing layer is a wire mesh braid.
`5. The catheter of claim 2 wherein
`reinforcing layer is a wire mesh braid.
`6. The catheter of claim 1 wherein
`reinforcing layer is a wire mesh braid.
`7. The catheter of claim 1 wherein the catheter is sterilized
`by exposure to gamma radiation.
`8. The catheter of claim 1 wherein the catheter is devoid
`of polytetrafluoroethylene.
`9. A catheter comprising:
`an elongate tube having a proximal end and a distal end
`defining an inner lumen and a wall with an annular
`croSS Section of a Substantially uniform thickness
`between the distal end and the proximal end and with
`an exposed innermost liner formed from a material
`consisting essentially of a copolymer of polyvinylidene
`fluoride and hexafluoropropylene and an outer poly
`meric jacket;
`wherein the catheter is stable upon exposure to gamma
`radiation.
`
`the intermediate
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`the intermediate
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`10. The catheter of claim 9 wherein the inner liner has a
`thickness of between about 0.001 inches (0.0025 cm) and
`about 0.005 inches (0.0127 cm).
`11. The catheter of claim 10 wherein the catheter further
`includes a Soft flexible tip formed from a material including
`polyether block amide affixed to the distal end of the
`elongate tube.
`12. The catheter of claim 9 wherein the catheter further
`includes a Soft flexible tip formed from a material including
`polyether block amide affixed to the distal end of the
`elongate tube.
`13. The catheter of claim 9 wherein the catheter is
`Sterilized by exposure to gamma radiation.
`14. The catheter of claim 9 wherein the catheter is devoid
`of polytetrafluoroethylene.
`15. A catheter comprising:
`an elongate proximal tube having a proximal end and a
`distal end with an exposed innermost inner liner formed
`from a material including a copolymer of polyvi
`nylidene fluoride and hexafluoropropylene, an interme
`diate reinforcing layer and an Outer jacket formed from
`a material including a blend of nylon and polyether
`block amide or polyether block amide alone; and
`a Soft flexible tip formed from a material including
`polyether block amide affixed to the distal end of the
`elongate proximal tube;
`wherein the catheter is stable upon exposure to gamma
`radiation.
`16. The catheter of claim 15 wherein the material forming
`the outer jacket has a hardneSS in the range of about 63D to
`about 72 D and the material forming the soft flexible tip has
`a hardness in the range of about 25 D to about 40 D.
`17. The catheter of claim 15 wherein the intermediate
`reinforcing layer is a wire mesh braid.
`18. The catheter of claim 15 wherein the inner liner
`consists essentially of a copolymer of polyvinylidene fluo
`ride and hexafluoropropylene.
`19. The catheter of claim 15 wherein the catheter is
`Sterilized by exposure to gamma radiation.
`20. The catheter of claim 15 wherein the catheter is devoid
`of polytetrafluoroethylene.
`21. A catheter comprising:
`an elongate tube having a proximal end and a distal end
`defining an inner lumen and a wall with an annular
`croSS Section of a Substantially uniform thickness
`between the distal end and the proximal end and with
`an exposed innermost liner formed from a material
`including a copolymer of polyvinylidene fluoride and
`hexafluoropropylene and an outer polymeric jacket;
`wherein the catheter is stable upon exposure to gamma
`radiation.
`22. The catheter of claim 21 wherein the inner liner has a
`thickness of between about 0.001 inches (0.0025 cm) and
`about 0.005 inches (0.0127 cm).
`23. The catheter of claim 21 wherein the catheter further
`includes a Soft flexible tip formed from a material including
`polyether block amide affixed to the distal end of the
`elongate tube.
`24. The catheter of claim 21 wherein the inner liner
`consists essentially of a copolymer of polyvinylidene fluo
`ride and hexafluoropropylene.
`25. The catheter of claim 21 wherein the catheter is
`Sterilized by exposure to gamma radiation.
`26. The catheter of claim 21 wherein the catheter is devoid
`of polytetrafluoroethylene.
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`Medtronic Exhibit 1476
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`5,860,963
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`7
`27. A catheter comprising:
`an elongate proximal tube having a proximal end and a
`distal end with a plasma etched exposed innermost liner
`formed from a material including a copolymer of
`polyvinylidene fluoride and hexafluoropropylene, an
`intermediate reinforcing layer, and an outer jacket
`formed from a material including a blend of nylon and
`polyether block amide or polyether block amide alone;
`and
`a Soft flexible tip formed from a material including
`polyether block amide affixed to the distal end of the
`elongate proximal tube,
`wherein the catheter is stable upon exposure to gamma
`radiation.
`28. The catheter of claim 27 wherein the material forming
`the outer jacket has a hardneSS in the range of about 63D to
`about 72 D and the material forming the soft flexible tip has
`a hardness in the range of about 25 D to about 40 D.
`29. The catheter of claim 27 wherein the intermediate
`reinforcing layer is a wire mesh braid.
`30. The catheter of claim 27 wherein the inner liner
`consists essentially of a copolymer of polyvinylidene fluo
`ride and hexafluoropropylene.
`31. The catheter of claim 27 wherein the catheter is
`Sterilized by exposure to gamma radiation.
`32. The catheter of claim 27 wherein the catheter is devoid
`of polytetrafluoroethylene.
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`33. A catheter comprising:
`an elongate tube having a proximal end and a distal end
`defining an inner lumen and a wall with an annular
`croSS Section of a Substantially uniform thickness
`between the distal end and the proximal end and with
`a plasma etched exposed innermost liner formed from
`a material including a copolymer of polyvinylidene
`fluoride and hexafluoropropylene and an outer poly
`meric jacket;
`wherein the catheter is stable upon exposure to gamma
`radiation.
`34. The catheter of claim 33 wherein the inner liner has a
`thickness of between about 0.001 inches (0.0025 cm) and
`about 0.005 inches (0.0127 cm).
`35. The catheter of claim 33 wherein the catheter further
`includes a Soft flexible tip formed from a material including
`polyether block amide affixed to the distal end of the
`elongate tube.
`36. The catheter of claim 33 wherein the inner liner
`consists essentially of a copolymer of polyvinylidene fluo
`ride and hexafluoropropylene.
`37. The catheter of claim 33 wherein the catheter is
`Sterilized by exposure to gamma radiation.
`38. The catheter of claim 33 wherein the catheter is devoid
`of polytetrafluoroethylene.
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`Page 7
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`Medtronic Exhibit 1476
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